title: Synthesizing and staining manganese oxide nanoparticles for cytotoxicity and cellular uptake investigation.
abstract: BACKGROUND
  For decades, contrast agents have been used to reduce longitudinal (T1) or transverse (T2) relaxation times. High toxicity of gadolinium-based contrast agents leads researchers to new T1 contrast agents. Manganese oxide (MnO) nanoparticle (NP) with the lower peril and good enough signal change ability has been offered as a new possibility for magnetic resonance imaging (MRI).
  
  
  METHODS
  The synthesized NPs were investigated for physicochemical and biological properties by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscope, dynamic light scattering (DLS), inductively coupled plasma, enzyme-linked immunosorbent assay, and 3T magnetic resonance imaging.
  
  
  RESULTS
  Due to physical contact importance of T1 contrast agents with tissues' protons, extremely thin layer of the surfactant, less than 2nm, was coated on NPs for aqueous stabilizing. The hydrophilic gentisic acid with low Dalton, around 154, did that role truly. Moreover, decreasing NP size to 5nm which increases available surface for the proton relaxation is another important parameter to reach an appropriate longitudinal relaxation rate. The NPs didn't reveal any side effects on the cells, and cellular uptake was considerable.
  
  
  CONCLUSIONS
  The synthesized NPs represented a promising result in comparison to clinical gadolinium chelates, due to higher r1 relaxivity and lower toxicity.
  
  
  CONCLUSIONS
  In addition to considerable signal change and cellular uptake, Prussian blue was tried on MnO NPs for the initial time, which can be observed within cells by pale blue color.
authors.affiliation: Department of Materials Science and Engineering, Sharif University of Technology, Azadi Ave., 14588-9694 Tehran, Iran; Research Center for Science & Technology in Medicine, Imam Khomeini Hospital, Tehran, Iran. Electronic address: h_omid@alum.sharif.edu.
authors.forename: Hamed
authors.initials: H
authors.lastname: Omid
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Oghabian
authors.forename: Reza
authors.initials: R
authors.lastname: Ahmadi
authors.forename: Narges
authors.initials: N
authors.lastname: Shahbazi
authors.forename: Hamid Reza Madaah
authors.initials: HR
authors.lastname: Hosseini
authors.forename: Saeed
authors.initials: S
authors.lastname: Shanehsazzadeh
authors.forename: Rashin Namivandi
authors.initials: RN
authors.lastname: Zangeneh
mesh_terms: D017209:Apoptosis; D049109:Cell Proliferation; D004797:Enzyme-Linked Immunosorbent Assay; D005841:Gentisates / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D008279:Magnetic Resonance Imaging; D017895:Manganese Compounds / Q000737:chemistry*; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010316:Particle Size; D013054:Spectrophotometry, Atomic; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D005841:Gentisates; D017895:Manganese Compounds; D010087:Oxides; C027424:manganese oxide; C010925:2,5-dihydroxybenzoic acid
keywords: Cell uptake; Cytotoxicity; MRI contrast agent; Manganese oxide nanoparticle; Prussian blue staining